Tractor



Aug. 17, 1937. L CONTRATTO 2,090,344

TRACTOR Original Filed May 25, 1934 hufig7 gni/zz@ y fm@ Patented ug.17, 1937 cargar @carries TRACTOR Laurenz Contratto, Sisikon, SwitzerlandOriginal application May 25, 1934, Serial No.

2 Claims.

My present invention relates to tractors and is divided from applicationSerial No. 727,487 filed 25th May 1934.

The invention relates more especially to improvements in tractors of thechange wheel type viz., having two pairs of traction wheels, which canbe alternatively used: One pair of relatively large diameter having Widerims and cleats attached thereon, hereinafter briefly called farmingwheels, and being designed to travel on soft soil as in ploughing,-ditching etc., and another pair of smaller wheels, designed to carrythe tractor over hard roads as in hauling and the transportation ofgoods.

The primary object of this invention is to provide an improved changeWheel structure for tractors, so designed that the farming wheels can bespeedily thrown out of operation and exchanged by the driver of thetractor for the road wheels, without the aid of tools such as wrenches,tongues of special design etc., and in much shorter periods of time thanwith tractor designs used heretofore.

In connection therewith the invention aims at providing a change wheelstructure of improved design for tractors, in which the farming wheelsare structurally so associated with the road wheels, that the latter canbe lifted to a relatively great hight above the ground, and so that thetractor can be freely driven over deeply ploughed ground and also overextraordinarily soft soils including peat, marshland etc., into whichthe tractor may sink to a considerable depth, without incurring the riskof the road wheels coming into contact with clods or other obstructions.

Another object of the invention will become incidentally apparenthereinafter to practitioners in this art.

The nature and scope of the invention are briefly outlined n theappended claims and will be more thoroughly understood by the followingspecification taken together with the: accompanying drawing which showsa section taken vertically through a change Wheel structure for tractorsdesigned according to this invention and shown by way of an example.

The change wheel structure for tractors designed according to thisinvention essentially comprises a rotary shaft 3 representing one of therear axles of thel tractor and being called hereinafter primary drivingshaft, a wheel I,here inafter called farming wheel, which is adapted asto the width of its rim to travel on soft ground and is preferablyprovided with cleats 2; the tubular hub 4 of said farming wheel is keyedto Divided and this application February 26, 1935, Serial No. 8,327.

In Germany May 2.7, 1933 Renewed July the primary shaft 3; a hollowmember 6, hereinafter called gear box, which is rotatably mountedpreferably by means of ball bearings 5, 5 on the hub 4 of the farmingwheel I in excentric position to the latter and is adapted to be swungaround the said hub, so as to change its angular position relatively tothe farming wheel I; self locking means under the drivers control forswinging said gear box 6 around the hub 4 of the farming wheel.

As shown in the drawing said self locking means comprise a worm gear I2,I3, the spindle I3 of which being preferably so long as to be in reachfrom the drivers seat and having a hand wheel (not shown) attached.

Another rotary shaft 8, hereinafter called secondary shaft is journalledon ball bearings 1, 'I' in the gear box 6 so as to extend substantiallyparallel to the primary shaft 3. A traction Wheel 9, herein called roadwheel, is secured to the said secondary driven shaft 8 and bears apneumatic tire. The said primary and secondary shafts are interconnectedby a toothed gear comprising a spur wheel I I having internal teeth andbeing secured to the spokes of the farming wheel concentrically thereto,and a pinion I9 attached to the secondary shaft 8 meshing with the spurwheel II. According to this invention the ratio of gearing is so chosen,that the road wheel 9 while on duty Will attain a considerably greaterspeed than the farming wheel I. The road wheel 9 is lowered to theground so as to carry the tractor by swinging the gear box 6 around anangle f about 180 on operating on the self locking means I2, I3.

A hood in the form of a cylindrical drum I4, which projects at I into anannular groove; in the body of the farming Wheel I encloses the gear box6 and worm gear I2, I3 for safe-guarding the change wheel mechanismincluding the Worm gear against being accidentally clogged by earth.

Many other changes and modications may conveniently be made in thestructural details of the change wheel attachment for tractors, asdescribed, without substantially departing from the spirit and thesalient features of this invention.

What I claim is:

1. A change Wheel structure for tractors and the like, including atractor frame, a farming wheel carried thereby and including a hub, agear box eccentrically mounted on the hub, means for adjusting the gearbox relative to the hub and holding it in adjusted position, a secondaryshaft mounted in the gear box in parallelism to and beyond the hub ofthe farming wheel, a road Wheel carried by the secondary shaft beyondthe ,vertical plane of the farming Wheel, an annular gear rack carriedby the frame of the tractor concentric with the hub of the farmingWheel, and a gear carried by the secondary shaft and in constant meshwith the annular gear rack, the eiecentricity of the gear box permittingthe road Wheel to be bodily moved to an operative position in a planebelow the ground engaging plane of the farming Wheel or to aninoperative -Wheel raising the farming wheel free of ground contact.

2. A construction as defined in claim 1, wherein thel gear box anddriving means for the road Wheel are housed within the axial length ofthe farming Wheel and wherein al closure protects the gear box anddriving means against external influences.

LAURENZ CONTRATTO.

